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What Is Application Performance Monitoring?


By RevDeBug

In a world where there’s an application for anything, it’s easy to see why application performance is so important. It’s simple, users expect applications to be fast, reliable, and simple to use. As a result, errors and performance issues can turn them away very quickly.

The thing is, over time, applications have also become far more complex than they were just a few years ago. This makes it even more challenging for businesses to optimize their applications’ performance. 

Yet, it’s crucial that they do, especially considering that, for many businesses, their application is their business. So, it’s vital to implement the right tools and strategies to achieve it. And those that succeed, set themselves up for increased growth and profitability. 

Here, application performance monitoring is an invaluable tool. In this post, we’ll take a closer look at it, why it’s important, and why businesses should use it.  

What Is Application Performance Monitoring?

So, what exactly is application performance monitoring? Application performance monitoring or APM is a set of tools for monitoring application availability and performance. In other words, APM is a method of detecting issues and tracking application performance to ensure that everything runs as it should. 

Businesses do this to ensure that their IT environment meets performance standards and allows them to identify bugs and potential issues while providing stellar user experiences. So, in short, APM allows businesses to maximize application efficiency and optimize the end-user experience.

For businesses to do this, they need the right tracking system or tools, experts to analyze the data, and key performance indicators (KPIs) that will show them how their application performs. Here, APM tools are a vital first step to ensure optimal application performance. These tools are available in a wide variety of forms. 

They can, for example, be simple tools to measure an application’s loading time, or sophisticated tools that use the power of artificial intelligence (AI) to gather and analyze data from a variety of sources to predict and react to errors or performance problems.

Irrespective of the tool used, it should provide businesses with all the information they need to identify and fix performance issues before they happen and affect the end-user. In short, APM solutions should show businesses when and where the end-user is affected and why the issue occurred. This, in turn, allows businesses to act proactively and react to issues faster.

The Need for Modern APM

APM has been a crucial tool for IT teams for years. Even though its use has remained constant during this time, APM has changed considerably to adapt to changing market demands and advances in technology. 

This, ultimately, means that, as new trends come and go and new technologies emerge, APM needs to keep up. As a result, APM solutions of just a mere few years ago are no longer sufficient in meeting the demanding needs, requirements, and modern workloads of IT teams. This is mainly due to two reasons, complexity, and user expectations.


The first reason why legacy APM tools and solutions are no longer sufficient is the complexity of modern applications. In simple terms, the new generation of applications is far more complex than their predecessors. 

A major contributor to this is the emergence and popularity of microservices-based architectures, containers, serverless functions, multi-cloud deployments, and similar trends. So, unlike older applications that run on a single server, modern applications are now spread across a variety of servers and abstracted away from the underlying infrastructure by containers.

In addition, many of these applications also depend on storage solutions that exist separately from the application itself which, in turn, requires the use of APIs to access the data. Not least of all is the scale of these systems that need to be monitored.

Combined, these all add to the complexity of modern applications that need to be managed and monitored so that businesses can ensure optimized application performance.

End-user Experience

The second reason why legacy APM solutions and tools are no longer sufficient for modern applications is fundamentally changed user expectations. It’s simple, nowadays end-users expect applications to be fast, reliable, intuitive, and easy to use.

It’s therefore vital that businesses be proactive and identify issues before they impact the end-user. This is perfectly illustrated when looking at the statistics. For example:

  • Over 50% of all visitors to websites and users of web applications who use mobile devices will leave a site or application if it doesn’t load within 3 seconds.
  • Almost 90% of mobile users will stop using an application if they experience performance problems.
  • 86% of customers who buy software are willing to pay more for it if it delivers a great user experience.

Considering the above, it’s easy to see why businesses that fail to be proactive in eliminating performance problems and, as such, deliver less-than-optimal user experiences run the risk of losing customers to competitors and damaging their reputation. In both cases, this could lead to a significant loss of revenue.

Here, it’s also important to keep in mind that APM is not only important for businesses that provide public-facing applications. Business applications also need to deliver reliable and fast performance to ensure efficiency, productivity, and disruptions to business processes.  

What Needs To Be Measured?

Now that we’ve looked at what APM is and why it’s important, let’s look at what businesses need to measure to ensure optimal performance and an excellent user experience. In other words, what metrics should businesses consider?

Before looking at these metrics, though, it’s important to understand, at the most basic level, how APM works. Typically, the key to ensuring optimal application performance is by understanding the health of every transaction or request that moves through an application. So, end-to-end APM:

  • Requires that businesses observe whether their applications are running as they should.
  • If not, it alerts them about the problem and collects valuable data about the source of the issue.
  • Analyzes the data in the context of the impact of the error or reduced performance on the business.
  • Allows businesses to adapt their application environment to identify and fix similar issues before they affect the business or the user experience.

Simply put, APM tracks and gathers information on almost every aspect that has an impact on application availability and performance. With that in mind let’s look at some of the most crucial APM metrics that businesses should monitor.

CPU, Disk, and Memory Usage

CPU, disk, and memory usage are basic and critical performance metrics and are an essential part of APM. At its simplest, businesses need to track and monitor CPU usage, memory demands, and disk read and write operations. In addition, they should also track per server or virtual machine usage as well as aggregate usage across all the deployed instances of an application.

Ultimately, this ensures that application performance is not affected by CPU, disk, or memory usage.

Error Rates

Error rates are simply the rate at which errors occur in an application or, in other words, how many times application performance declines or fails. While the idea is to have as few errors as possible, tracking error rates also allow businesses to act more proactively and respond to errors quicker.

Typically, there are three ways to track this metric:

  • HTTP Error Percent. This is the number of web requests made by users that end in an error.
  • Logged Exceptions. This is the number of unhandled and logged errors that occur in an application. 
  • Thrown Exceptions. This is the number of all exceptions that have been thrown.

Error rates may impact or be connected with other metrics you are tracking CPU, storage, and memory usage. Connecting information from different metrics it’s also important to incorporate provide valuable information and allow to resolve issues faster. 

Response Times

Response times allow businesses to determine whether the speed is affecting their application’s performance. Here, average response time is probably the most popular metric to monitor. 

It is, however, important to keep in mind that average response time, although useful, should align with a business’s goals. In this way, they’ll be able to properly gauge if speed is affecting their performance and, by implication, their business. One slower request doesn’t impact application performance but repeating situations over time may by implication of serious issues and potential problems with further application scaling to larger traffic.

Number of Instances

Because cloud computing allows an application to scale up or down depending on the circumstances and user demand, businesses must know how many instances of an application or server is running at any given time.

If this number isn’t optimal, it could either mean lower application performance or higher infrastructure bills. As a result, businesses should track this metric to automate resource allocation optimally.

Request Rates

Request rates measure how much traffic an application receives. It also provides insights into spikes in activity or periods of inactivity and is very useful for correlating to other APM metrics. In simple terms, almost every other essential performance metric relating to an application’s performance is affected by the increases and decreases in the traffic it receives.

For this reason, request rates are an essential metric to track and monitor to ensure optimal application performance.

Application Availability

Application availability monitors whether a business’s application is online and available or not. It’s also the metric most businesses use to check and ensure compliance with service level agreements (SLAs). Because compliance with SLAs and application uptime are both crucial for a business’s success, application availability is a key performance metric to track and monitor.

Garbage Collection

Applications written in Java, C#, or other programming languages that use garbage collection can use a lot of memory. Garbage collection can cause processes to suspend, applications to freeze, and CPU usage to increase significantly. 

The problem is that, due to garbage collection, any issues causing performance to decline could remain hidden. As a result, it’s vital that businesses that deploy applications written in these languages, monitor this metric to ensure optimal performance. 

User Satisfaction

User satisfaction is probably the most important metric to measure as it reflects how users feel about their experience using an application. It’s typically measured using the application performance index or Apdex score which has become an industry standard for tracking and monitoring the performance of an application.

It simply works by specifying a goal for how long a specific request or transaction should take once a user makes a request or performs a transaction. Based on this score, businesses are then able to understand how the user experience is impacted by their application’s performance and make improvements were necessary.


Tracing is a metric that helps businesses understand and analyze the flow of every user transaction or request as it moves between different modules of an application. With it, businesses can identify the exact point in the application where the user experience is negatively impacted. As a result, they’re able to isolate and address these issues to improve the application’s performance and the user experience.

Why APM Matters

We’ve now looked at why there’s a need for APM and the important metrics to monitor. The only question remaining is why businesses should use it if they’re using alternative methods to manage their application’s performance. These methods typically include synthetic transactions, manual instrumentation, and customer feedback.

The problem with these methods is that, while they are perfectly adept at showing when issues have occurred, they don’t show businesses why these issues occurred. As a result, they don’t allow businesses to act proactively in ensuring optimal application performance.

And that’s where APM comes in. As shown above, it allows businesses to track the availability and performance of their applications and, as such, deliver exceptional user experiences. Because it’s able to automate the application monitoring and management process it also saves businesses a lot of time, effort, and costs in the process.

APM Done Right

Finally, for those businesses that do implement APM, there are always ways to improve its implementation and increase the chances of success in optimizing application performance and the user experience. With that in mind, let’s look at some of these in more detail.

The Right Tools

There are many different APM solutions available that businesses can use to monitor and manage application performance, each with its own set of tools. As a result, businesses must choose the right solution for their specific needs and requirements. 

No matter what the tool, though, it should be easy and intuitive to use, focus on the user experience, and turn data into actionable insights that businesses can use to improve their application’s performance.

The Right Rules

What metrics a business tracks depends on its business goals and the outcomes it wants to achieve. We’ve mentioned some key metrics earlier but keep in mind there or others that businesses can consider. It’s also important when deciding on the right metrics to monitor, that businesses assign target numbers and goals to achieve. 

More importantly, though, an APM solution must be configured to the business’s unique challenges. If it isn’t, the value that the business will gain from using the solution will diminish. 

The Right People

We mentioned earlier that APM not only relies on the right tools but also the experts necessary to analyze the data, gain insights from it, and implementing necessary measures to optimize application performance.

The perfect team of experts should include the team tasked with deploying APM and the developers who are in the best position to resolve application issues as they arise.

Go Beyond Being in Control

When monitoring application performance, it’s important to remember that there are always external factors that could impact application performance. Typically, unlike the specific application’s code or its deployment, these external factors are not within a business’s control.

So, while no one, including businesses, can control these variables, they can control what processes they put in place and what happens when these variables occur in the future.

Be the User

To a large extent, the success of a business’s application relies on the user experience. As mentioned earlier, users will easily abandon or even uninstall an application if they encounter errors or leave a website when they experience performance issues.

The perfect way to counter this is for businesses to put themselves in the user’s shoes. In this way, they’ll see what the user sees and experience what the user experiences. Ultimately, this allows them to optimize the user experience and ensure the success of their application. 

Automate, Automate, and Automate

It’s of little use to only identify and track system errors and not do anything about them. It’s, therefore, important that businesses configure APM solutions to provide alerts and take corrective action when an issue occurs with their application.

Ultimately, by automating these alerts and actions they save a lot of time and effort while keeping users satisfied. And when users are satisfied it, in turn, sets businesses up for success.

The Bottom Line

In a competitive market, optimized application performance is crucial. If it’s lacking, it will most certainly impact the user experience negatively. This, in turn, leads to users uninstalling applications and leaving websites, never to return. Ultimately, it can then have a significant effect on a business’s bottom line. 

Here at RevDeBug we take all the above into consideration – take a look at how we simplify this complex issue.

To prevent this, businesses need to ensure that their applications perform as they should and that they don’t suffer from performance issues. The perfect way to do this is to implement application performance monitoring that allows businesses to not only track and monitor application performance but also allows them to act proactively and resolve issues before they happen.

Hopefully, this post helped illustrate what APM is, why it’s important, and what metrics businesses should monitor. To find out more about APM, visit our website for more details.   

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